The present invention relates to a filter element for filtering impurities from air.
More specifically, the invention concerns a filter element that comprises one or more filters whereby each filter is composed of an inlet piece that is connected to a filter bag whereby this filter element is intended for removing dust, dirt and other impurities in the solid phase present in the air.
In particular the invention is for ventilation units that are used in buildings and similar and is specifically focused on static filtration.
Such conventional filter elements of the bag filter type are already known and are used for example in filter devices of climate controllers, air purification systems, compressors, gas turbines, in order to remove impurities from the air to ensure that the impurities cannot hinder the good operation of the equipment or to ensure that the air remains clean.
Using the filter device in which the filter element is affixed all kinds of impurities can be removed from the air to be filtered, because the filter element is provided with a filter through which air can flow but which is impermeable to impurities.
To this end the filter is made from a suitable material according to the application and type of impurities, for example.
It is known that the design of filter elements has not changed for a long time.
With such traditional filter elements the form is not optimum for realising a good flow of air.
A square or rectangular cross-section of the inlet opening of the filter bag is often used, but this form causes high flow resistance for the air and a large pressure drop in the air around the device.
This has the disadvantage that more energy is needed to guide and filter the same volume of air through the filter element.
The form of the filter bag is not aerodynamic either, such that the air resistance over the entire surface of the filter is relatively high and is not constant either.
This will be detrimental to the efficient operation of the filter element, as not all of the surface of the filter bag is used to an equal extent.
As a result dust, dirt and impurities can accumulate locally more quickly and the filter bag can become saturated faster.
Other types of filter elements are also known that are not a bag filter, but consist of folded filter media such as described in EP 2.537.571 for example. These filter elements are a completely different type and are used in filter devices for removing dust, whereby they can be cleaned by means of ‘pulse cleaning’, for example.
According to the applicant, with such filter elements the form of the filter itself is far from optimum and is not adapted to obtain a good flow of air.
The flow through the filter element is from the outside of the filter element to the inside. In other words: this is the opposite of the conventional flow through a bag filter.
In the opinion of the applicant, filter elements as described in U.S. Pat. No. 1,821,202 are not of optimum form. Furthermore, here it concerns the replaceability of the filter medium that is fastened in a metal basket. The filter capsules are fastened in a fixed wall, this is in contrast to bag filters, where the bags are fastened in a frame.